syslog-ng documentation

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The syslog-ng product family has an extensive documentation, covering everything from how to install a product to the most complex configuration and settings descriptions. If you cannot find an answer to your question, try the mailing list - our community is always eager to help.

You can list all active metrics on your syslog-ng PE host using the following command (this lists the metrics, without their current values): syslog-ng-ctl query list "*"

To list the metrics and their values, use the following command: syslog-ng-ctl query get "*"

The displayed metrics have the following structure.

The type of the object (for example dst.file, tag, src.facility)

The ID of the object used in the syslog-ng configuration file, for example d_internal or source.src_tcp. The #0 part means that this is the first destination in the destination group.

The instance ID (destination) of the object, for example the filename of a file destination, or the name of the application for a program source or destination.

The status of the object. One of the following:

a - active. At the time of quering the statistics, the source or the destination was still alive (it continuously received statistical data).

d - dynamic. Such objects may not be continuously available, for example, like statistics based on the sender's hostname. These counters only appear above a certain value of stats-level() global option:

host: source host, from stats-level(2)

sender: sender host, from stats-level(3)

program: program, from stats-level(3)

Example 16.1. Dynamic counters

The following example contains 6 different dynamic values: a sender, a host, and four different programs.

To avoid performance issues or even overloading syslog-ng PE, you might want to limit the number of registered dynamic counters in the message statistics. To do this, configure the Section stats-max-dynamics() global option.

o - This object was once active, but stopped receiving messages. (For example a dynamic object may disappear and become orphan.)

Note

The syslog-ng PE application stores the statistics of the objects when syslog-ng PE is reloaded. However, if the configuration of syslog-ng PE was changed since the last reload, the statistics of orphaned objects are deleted.

The type of the statistics:

processed: The number of messages that successfully reached their destination driver. Note that this does not necessarily mean that the destination driver successfully delivered the messages (for example, written to disk or sent to a remote server).

dropped: The number of dropped messages — syslog-ng PE could not send the messages to the destination and the output buffer got full, so messages were dropped by the destination driver, or syslog-ng PE dropped the message for some other reason (for example, a parsing error).

queued: The number of messages passed to the message queue of the destination driver, waiting to be sent to the destination.

suppressed: The number of suppressed messages (if the suppress() feature is enabled).

stamp: The UNIX timestamp of the last message sent to the destination.

discarded: The number of messages discarded by the given parser. These are messages that the parser could not parsed, and are therefore not processed. For example:

parser;demo_parser;;a;discarded;20

memory_usage: The memory used by the messages in the different queue types (in bytes). This includes every queue used by the object, including memory buffers (log-fifo) and disk-based buffers (both reliable and non-reliable). For example:

dst.network;d_net#0;tcp,127.0.0.1:9999;a;memory_usage;0

Note that the memory usage (size) of queues does not equal to the memory usage (size) of the log messages in syslog-ng PE. A log message can be in multiple queues, thus its size is added to multiple queue sizes. To check the size of all log messages, use global.msg_allocated_bytes.value metric.

matched: The number of messages that are accepted by a given filter. Available for filters and similar objects (for example, a conditional rewrite rule). For example, if a filter matches a specific hostname, then the matched counter contains the number of messages that reached the filter from this hosts.

filter;demo_filter;;a;matched;28

not_matched: The number of messages that are filtered out by a given filter. Available for filters and similar objects (for example, a conditional rewrite rule). For example, if a filter matches a specific hostname, then the not_matched counter contains the number of messages that reached the filter from other hosts, and so the filter discarded them. Note that since the not_matched metric applies to filters, and filters are expected to discard messages that do not match the filter condition, not_matched messages are not included in the dropped metric of other objects.

filter;demo_filter;;a;not_matched;0

written: The number of messages successfully delivered to the destination. This value is calculated from other counters: written = processed - queued - dropped. That is, the number of messages syslog-ng PE passed to the destination driver (processed) minus the number of messages that are still in the output queue of the destination driver (queued) and the number of messages dropped because of an error (dropped, for example, because syslog-ng PE could not deliver the message to the destination and exceeded the number of retries).

This metric is calculated from other metrics. You cannot reset this metric directly: to reset it, you have to reset the metrics it is calculated from.